After drilling a wellbore that intersects a subterranean hydrocarbon-bearing formation, a variety of wellbore tools may be positioned in the wellbore during completion, production, or remedial activities. For example, temporary packers may be set in the wellbore during the completion and production operating phases of the wellbore. In addition, various operating tools including flow controllers (e.g., chokes, valves, etc.) and safety devices such as safety valves may be releasably positioned in the wellbore.
A number of subsurface wellbore devices such as plugs, safety valves, packers, and the like may be used when performing subterranean operations. Such tools are generally lowered downhole by either a wireline or a working string and may be configured with a fishing neck to facilitate recovery at a later time. Once downhole, the tool may be set at a desired location and released, allowing the wireline or work string to be retrieved.
The setting and retrieving of such tools may be performed mechanically by a work string or wireline or by electrically actuated power units. Electrically actuated power units may utilize a conductor in the wireline to accomplish actuation by surface power, after the tool is properly positioned. Alternatively, self-contained Downhole Power Units (“DPUs”) which do not require electrical power from the surface and therefore permit using a slickline rather than a wireline may be used. The use of DPUs is desirable because of their relative speed and efficiency of use.
However, because DPUs are not powered from the surface, they can only apply a limited amount of force. Further, conventional DPUs are relatively long to prevent exposure of parts to wellbore pressure. It is desirable to develop a more compact DPU that can provide greater force than that supplied by traditional DPUs.
The disclosure may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the disclosure being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.